Much of railroad traffic in the USA is on single track for both directions. But these are called Block Signals. White is for proceed at authorized speed. Yellow, indicates that the next block signal is Red. It is a violation of operating rules to even nose past a Red signal. Single track necessitates a train go into a siding to give way to an oncoming train. These traffic signals, when properly observed, especially prevent head on and rear end collisions. Dispatcher decides which one is to go into siding for the meet, not the train crews.
Yes, they do.
Traffic signals. NO
They have train signals that look similar to those that decades later were adopted for road users.
Have been in use for over 100 years.
Yes they do
Yes and somehwhat in the the same way we have them for automobiles. Red-Stop Green-Go Yellow- caution and indicates that the next signal is probably red.
Yes. there are visual signals to help direct trains, subways, etc.
Yes they do, keeps them from running into each other.